The macro addins can extend the Microsoft PowerPoint app on Windows or on Mac.
The macro can set handlers for various events in the presentation lifecycle:
When user closes the presentation document, PowerPoint will fire the PresentationClose event. When document is unsaved, PowerPoint will display a dialog box to save the file after this event handler code was executed.
If user choses to cancel the save file dialog box, the presentation will still be opened and user can work with it. This makes the PresentationClose unsuitable to clean up resources.
The PowerPoint 2010 on Windows added new event PresentationCloseFinal which is called if the presentation document is really closed.
It is the right event to clean up any unmaganed resources the macro or add-in may be working with.
The PresentationCloseFinal should be fired on PowerPoint on macOS at the same point when Windows version of PowerPoint does it.
The PresentationCloseFinal is never fired on PowerPoint on macOS.